imagecopymergegray

(PHP 4 >= 4.0.6, PHP 5, PHP 7, PHP 8)

imagecopymergegray — Copie et fusionne une partie d'une image en niveaux de gris

Description

imagecopymergegray(
    GdImage $dst_image,
    GdImage $src_image,
    int $dst_x,
    int $dst_y,
    int $src_x,
    int $src_y,
    int $src_width,
    int $src_height,
    int $pct
): bool

imagecopymergegray() copie une partie de l'image src_image dans l'image de destination dst_image commençant aux coordonnées (src_x, src_y), avec la largeur src_width et la hauteur src_height. La zone de l'image ainsi définie sera copiée aux coordonnées (dst_x, dst_y), dans l'image de destination.

imagecopymergegray() est identique à la fonction imagecopymerge(), hormis le fait que lors de la fusion, le "hue" de l'image sera conservé grâce à la conversion de la zone dans l'image de destination en gris, avant l'opération de copie.

Liste de paramètres

dst_image: Ressource cible de l'image.
src_image: Ressource source de l'image.
dst_x: X : coordonnée du point de destination.
dst_y: Y : coordonnée du point de destination.
src_x: X : coordonnée du point source.
src_y: Y : coordonnée du point source.
src_width: Largeur de la source.
src_height: Hauteur de la source.
pct: Le paramètre src_image sera changé en niveaux de gris en accord avec le paramètre pct où 0 correspond à une convertion totale en niveaux de gris et 100 ne modifie rien. Lorsque pct = 100, cette fonction se comporte de la même façon que la fonction imagecopy() pour les palettes, sauf pour l'ignorance des composants alpha, alors qu'elle implémente la transparence alpha pour les images true colour.

Valeurs de retour

Cette fonction retourne true en cas de succès ou false si une erreur survient.

Historique

Version	Description
8.0.0	`dst_image` et `src_image` attendent désormais des instances de GdImage ; auparavant, des resources étaient attendues.

Exemples

Exemple #1 Exemple avec imagecopymergegray()

<?php
// Création des instances d'image
$dest = imagecreatefromgif('php.gif');
$src = imagecreatefromgif('php.gif');

// Copie et fusionne - Gris = 20%
imagecopymergegray($dest, $src, 10, 10, 0, 0, 100, 47, 20);

// Affichage et libère la mémoire
header('Content-Type: image/gif');
imagegif($dest);

imagedestroy($dest);
imagedestroy($src);
?>

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User Contributed Notes 8 notes

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amezghal at msn dot com ¶

16 years ago


gray effect :)
<?php
header('content-type:image/png');
$url_img = 'my_image.png';
$img = imagecreatefrompng($url_img);
$x = imagesx($img);
$y = imagesy($img);
$gray_img = imagecreatetruecolor($x, $y);
imagecolorallocate($gray_img, 0, 0, 0);
for ($i = 0; $i < $x; $i++) {
  for ($j = 0; $j < $y; $j++) {
    $rgb = imagecolorat($img, $i, $j);
    $r = ($rgb >> 16) & 0xFF;
    $g = ($rgb >> 8) & 0xFF;
    $b = $rgb & 0xFF;
     //for gray mode $r = $g = $b
    $color = max(array($r, $g, $b));
    $gray_color = imagecolorexact($new_img, $color, $color,   $color);
     imagesetpixel($gray_img, $i, $j, $gray_color);
   }
}
?>

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Mark Barba ¶

19 years ago


//  Using the same code I found here on php.net, 
// I was able to figure out how to convert GIF (or any other
// format GD supports) to CIP format.  CIP is the image
// format for Cisco IP Phones...  7905/7940 and 7960 
// models...  Hope someone finds this useful and make it 
// better...  

/////// GIF2CIP PHP code ///////

// Convert image in memory to grayscale
    $img_width  = imageSX($im2);
    $img_height = imageSY($im2);

   // convert to grayscale
   // note: this will NOT affect your original image, unless
   // originalFileName and destinationFileName are the same
   for ($y = 0; $y <$img_height; $y++) { 
       for ($x = 0; $x <$img_width; $x++) { 
           $rgb = imagecolorat($im2, $x, $y);
           $red  = ($rgb >> 16) & 0xFF;
           $green = ($rgb >> 8)  & 0xFF;
           $blue  = $rgb & 0xFF;

           $gray = round(.299*$red + .587*$green + .114*$blue);
           
           // shift gray level to the left
           $grayR = $gray << 16;  // R: red
           $grayG = $gray << 8;    // G: green
           $grayB = $gray;        // B: blue
           
           // OR operation to compute gray value
           $grayColor = $grayR | $grayG | $grayB;

           // set the pixel color
           imagesetpixel ($im2, $x, $y, $grayColor);
           imagecolorallocate ($im2, $gray, $gray, $gray);
       }
   }
/////////////////////////////////////////////////////////

    // Modifies palette to only 4-colors (CIP Images on 7905/7940 & 7960 is 2-bit color)
    ImageTrueColorToPalette2($im2,FALSE,4);

    // Basic header for CIP Image files...
    header ("Content-type: text/xml");
    echo "<CiscoIPPhoneImage> ";
    echo "<LocationX>-1</LocationX> ";
    echo "<LocationY>-1</LocationY> ";
    echo "<Width>132</Width> ";
    echo "<Height>65</Height> ";
    echo "<Depth>2</Depth> ";
    echo "<Data>";

// get image dimensions (almost same code as above)
   $img_width  = imageSX($im2);
   $img_height = imageSY($im2);

   // convert to grayscale
   // note: this will NOT affect your original image, unless
   // originalFileName and destinationFileName are the same
   for ($y = 0; $y <$img_height; $y++) { 
       for ($x = 0; $x+4 <$img_width; $x = $x+4) 
       { 
            for ($ix = 0; $ix < 4; $ix++)
            {
               $rgb = imagecolorat($im2, $x + $ix, $y);

               // I came up with this translation on my own
               // Some smart person is bound to perfect it
               if ($rgb=="2") {$rgb=0;$Gray1[$ix] = $rgb;continue;}
               if ($rgb=="0") {$rgb=2;$Gray1[$ix] = $rgb;continue;}
               if ($rgb=="1") {$rgb=1;$Gray1[$ix] = $rgb;continue;}
               if ($rgb=="3") {$rgb=3;$Gray1[$ix] = $rgb;continue;}
           }
                $gray1 = $Gray1[0];
                $gray2 = $Gray1[1] << 2;
                $gray3 = $Gray1[2] << 4;
                $gray4 = $Gray1[3] << 6;
                
                // Pack 4 pixels into a single byte for CIP images
                $grey = $gray1 | $gray2 | $gray3 | $gray4;

                // CIP image data is sent in HEX, strtoupper is not really needed.
                $code = strtoupper(dechex($grey)); 

                // My quick fix to padding single HEX values
                if (strlen($code)==1) $code = "0".$code;
                echo $code;
                
       }

   }
    echo "</Data>";
    echo "<Title>$myvar</Title> ";
    echo "<Prompt>$city</Prompt> ";
    echo "</CiscoIPPhoneImage>";
    exit;

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switch251 at netcourrier dot com ¶

20 years ago


In addition to code_couturier too: his code will produce blue pictures, because the value he uses to set the pixel color (the code is incomplete: I first thought it should be $gray) is between 0 and 255, which corresponds to blue levels.

To convert the picture to grayscale, use the following code:

<?php
    // replace with your files
    $originalFileName    = "colorPicture.jpg";
    $destinationFileName = "bwPicture.jpg";
    
    // create a copy of the original image
    // works with jpg images
    // fell free to adapt to other formats ;)
    $fullPath = explode(".",$originalFileName);
    $lastIndex = sizeof($fullPath) - 1;
    $extension = $fullPath[$lastIndex];
    if (preg_match("/jpg|jpeg|JPG|JPEG/", $extension)){
        $sourceImage = imagecreatefromjpeg($originalFileName);
    }

    // get image dimensions
    $img_width  = imageSX($sourceImage);
    $img_height = imageSY($sourceImage);

    // convert to grayscale
    // note: this will NOT affect your original image, unless
    // originalFileName and destinationFileName are the same
    for ($y = 0; $y <$img_height; $y++) { 
        for ($x = 0; $x <$img_width; $x++) { 
            $rgb = imagecolorat($sourceImage, $x, $y);
            $red   = ($rgb >> 16) & 0xFF;
            $green = ($rgb >> 8)  & 0xFF;
            $blue  = $rgb & 0xFF;

            $gray = round(.299*$red + .587*$green + .114*$blue);
            
            // shift gray level to the left
            $grayR = $gray << 16;   // R: red
            $grayG = $gray << 8;    // G: green
            $grayB = $gray;         // B: blue
            
            // OR operation to compute gray value
            $grayColor = $grayR | $grayG | $grayB;

            // set the pixel color
            imagesetpixel ($sourceImage, $x, $y, $grayColor);
            imagecolorallocate ($sourceImage, $gray, $gray, $gray);
        }
    }

    // copy pixel values to new file buffer
    $destinationImage = ImageCreateTrueColor($img_width, $img_height);
    imagecopy($destinationImage, $sourceImage, 0, 0, 0, 0, $img_width, $img_height);

    // create file on disk
    imagejpeg($destinationImage, $destinationFileName);
    
    // destroy temp image buffers
    imagedestroy($destinationImage);    
    imagedestroy($sourceImage);
?>

Copy-paste, replace the file names on the top and there you go (picture files must be in same folder as this script. If not, you will have to do your own file management).

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mail at laeubi dot de ¶

21 years ago


This function don't work properly for me on trucolerimages (have not tried yet for other types) it jsut produce a part-grayscale image, and some color get mesed up.
I found a workaround here:
http://www.phpbuilder.com/columns/cash20030526.php3?page=2

[quote]
Advanced Image Editing Under the GD Library
Colorizing
Colorizing images is fairly easy to do. The easiest way to colorize an image is fairly simple to grasp. Create an image of the same dimensions and fill that image with the color you want to change it to. This new image is then placed on top of the older image, giving it a colorized look.

<?php 
function imagecolorize(&$im,&$col,$pct) { 
    // Get the image's width 
    $im_w = imagesx($im);  
    // Get the image's height 
    $im_h = imagesy($im);  
    // Set a pixel with the color, so we can get it easily 
    $setpixel = imagesetpixel($im,$im_w,0,$col);  
    // Get the color 
    $index = imagecolorat($im,$im_w,0);  
    // Find the color in the index 
    $rgb = imagecolorsforindex($im,$index);  
    // Get the red value 
    $r = $rgb["red"]; 
    // Get the green value 
    $g = $rgb["green"];  
    // Get the blue value 
    $b = $rgb["blue"];  
    // Create the layover 
    $layover = imagecreate($im_w,$im_h);  
    // Allocate the color on this image 
    $color = imagecolorallocate($layover,$r,$g,$b);  
    // Fill the image with the new color (this really isn't needed) 
    $fill = imagefill($layover,0,0,$color);  
    // Merge the layover on top of the older image 
    $merge = imagecopymerge($im,$layover,0,0,0,0,$im_w,$im_h,$pct); 
    imagedestroy($layover); // Destroy the layover 
} 
?> 

If we use a blue layover RGB(0,0,255), we get this result:
[/quote]

if you use black or gray, its not perfekt, but better than nothing ;)

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anonymous at domain dot com ¶

15 years ago


grayscale conversion is built-in with imagefilter(). 

<?php
     /* other code */

     $image = imagecreatefromjpeg('some.jpg');
     imagefilter($image, IMG_FILTER_GRAYSCALE);

     /* other code (ie save) */

     imagedestroy($image);

     /* other code */
?>

you could create the sepia effect by the following:

<?php
     /* other code */

     $image = imagecreatefromjpeg('some.jpg');
     imagefilter($image, IMG_FILTER_GRAYSCALE);
     imagefilter($image, IMG_FILTER_COLORIZE, 112, 66, 20);
     //Wikipedia RGB definition of sepia

     /* other code (ie save) */

     imagedestroy($image);

     /* other code */
?>

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szamil at ginf dot pl ¶

17 years ago


I've changed a little switch251's code and here we have sephia effect
<?php
   // replace with your files
    $originalFileName    = $filename;
    $destinationFileName = "2".$filename;
    
    // create a copy of the original image
    // works with jpg images
    // fell free to adapt to other formats ;)
    $fullPath = explode(".",$originalFileName);
    $lastIndex = sizeof($fullPath) - 1;
    $extension = $fullPath[$lastIndex];
    if (preg_match("/jpg|jpeg|JPG|JPEG/", $extension))
    {
        $sourceImage = imagecreatefromjpeg($originalFileName);
    }

    // get image dimensions
    $img_width  = imageSX($sourceImage);
    $img_height = imageSY($sourceImage);

    // convert to grayscale
    // note: this will NOT affect your original image, unless
    // originalFileName and destinationFileName are the same
    for ($y = 0; $y <$img_height; $y++) 
    { 
        for ($x = 0; $x <$img_width; $x++) 
        { 
            $rgb = imagecolorat($sourceImage, $x, $y);
            $red   = ($rgb >> 16) & 0xFF;
            $green = ($rgb >> 8)  & 0xFF;
            $blue  = $rgb & 0xFF;

          //sephia
            $red2 = min($red*.393 + $green*.769 + $blue*.189,255);
            $green2 = min($red*.349 + $green*.686 + $blue*.168,255);
            $blue2  = min($red*.272 + $green*.534 + $blue*.131,255);
            // shift gray level to the left
            
            $grayR = $red2 << 16;   // R: red
            $grayG = $green2 << 8 ;    // G: green
            $grayB = $blue2;         // B: blue
            
            // OR operation to compute gray value
            $grayColor = $grayR | $grayG | $grayB;

            
            // set the pixel color
            imagesetpixel ($sourceImage, $x, $y, $grayColor);
            imagecolorallocate ($sourceImage, $gray, $gray, $gray);
        }
    }

    // copy pixel values to new file buffer
    $destinationImage = ImageCreateTrueColor($img_width, $img_height);
    imagecopy($destinationImage, $sourceImage, 0, 0, 0, 0, $img_width, $img_height);

    // create file on disk
    imagejpeg($destinationImage, $destinationFileName);
    
    // destroy temp image buffers
    imagedestroy($destinationImage);    
    imagedestroy($sourceImage);
?>

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annonymous at example dot com ¶

20 years ago


in addition to code_couturier - try this formula to calculate gray-value (luminance) in his "more exact" way:

$gray = round(.299*$red + .587*$green + .114*$blue);

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code_couturier at graffiti dot net ¶

21 years ago


# very fast way to generate a grayscal-
# image from a true color image

#...

# --- quick grayscale image
for ($y = 0; $y <$img_height; $y++) { 
 for ($x = 0; $x <$img_width; $x++) { 

 # here we extract the green from 
 # the pixel at x,y , to use it as gray value
 $gray = (ImageColorAt($image, $x, $y) >> 8) & 0xFF;

 # a more exact way would be this:
 # $rgb = ImageColorAt($image, $x, $y);
 # $red = ($rgb >> 16) & 0xFF;
 # $green = (trgb >> 8) & 0xFF;
 # $blue = $rgb & 0xFF;
 # $gray = (int)(($red+$green+$blue)/4); 

 # and here we set the new pixel/color
  imagesetpixel ($image, $x, $y, 
  ImageColorAllocate ($image, $gray,$gray,$gray));
 }
}
 
# ...

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